The head of Libya's ruling National Transitional Council says his country's political turmoil threatens its already fragile stability and may take it to a "bottomless pit."

Mustafa Abdel Jalil was commenting Sunday on the previous night's violence in the city of Benghazi, when protesters forced their way into the headquarters of the transitional government, after surrounding the building for hours.

Abel Jalil, speaking to reporters in the eastern city, appealed for more time to address protesters' demands that the new government was not doing enough.

One witness said protesters armed with stones and iron bars ransacked offices at the NTC's headquarters late Saturday and attacked a car believed to belong to Abdel Jalil.

Earlier, some demonstrators threw home-made grenades, causing much noise but no reported injuries. Officials were forced to flee through a back door.

Many of the protesters were former fighters who had been injured during the nine-month civil war. They complained of being sidelined in the new Libya and a lack of transparency on the part of the country's new leaders.

The protesters also said government officials still in power despite ties to the ousted regime of slain former ruler Moammar Gadhafi should be fired.

Benghazi, Libya's second largest city and the birthplace of the revolt, was hit hard by government forces during the uprising to end Gadhafi's 41-year rule over the north African country.

Fighters loyal to the dictator — who was later captured and killed months later near his hometown of Sirte — launched a damaging bombing raid on the main rebel-held city in March 2011 as NATO fighter jets began their UN-mandated campaign to protect the civilians.

The NTC is backed by Western powers, yet still unelected. However, it's expected to soon pass laws that will specify how elections for a transitional parliament will be held.